psych lec 3- part 1-2025-02-04T02:06:45

Housekeeping

• Marks for guided article reviews are being released gradually. If marks have not been received yet, it's normal and expected to have notifications out by next week.

• Emphasis on originality in submissions; copying leads to plagiarism, impacting assessments.

• Encouragement to paraphrase and show comprehension of material instead of copying verbatim.

• Feedback should be directly addressed to the person who graded the assignment (TA or professor).

• Participation in studies can help recover marks lost in guided article reviews.

Upcoming Exam Details

• The exam will be in paper format (no laptops required) scheduled for next Thursday at 12:00 PM, lasting 90 minutes.

• Different sections have different exam dates and locations, check the syllabus for details.

• Structure: 62 multiple choice questions covering content from the initial class to today's session.

  • Approximate breakdown: 20 questions per topic including psychology basics, biology of the mind, sensation, and perception.

• Questions are arranged by topic to assist memory retrieval and understanding of major concepts.

• Knowledge of specific dates is not required but knowing significant events and concepts is advised, especially in historical contexts of psychology.

• Expect definitions and application-focused questions while keeping in mind tricky areas as identified in previous lectures and TA presentations.

• Bonus questions will be integrated into the exam but all questions should be answered to maximize scoring.

Sensation and Perception Overview

Key Concepts in Sensation

• Sensation: Raw data reception from the environment processed by sensory receptors (e.g., eyes, ears).

• Perception: Active interpretation and meaning assignment to sensed data.

• Process of sensation involves transduction, sensory reduction, and coding.

  • Transduction: Conversion of stimuli into neural impulses sent to the brain.

  • Sensory Reduction: Filtering of incoming sensations; not all sensed data is transmitted to the conscious brain.

  • Coding: Neural impulses follow different routes based on type and location of stimuli (e.g., visual data travels along the optic nerve to the occipital lobe).

Psychophysics Measurement

• Absolute Threshold: Smallest stimulus level detected 50% of the time.

• Just Noticeable Difference: Minimum difference required to detect change between stimuli.

• Sensory Adaptation: Decreased sensitivity to constant stimuli (e.g., ignoring repetitive noises).

Vision

• Electromagnetic Spectrum: Humans detect wavelengths from 400 (blue) to 700 (red) nanometers, while some species like bees detect UV light.

• Frequency and Amplitude: Determines color and brightness perception; high frequency equates to blue, low frequency equates to red; higher amplitude means brighter colors.

Anatomy of the Eye

• Focus on the eye structure:

  • Cornea: Initial light refraction point.

  • Pupil and Iris: Control light entry.

  • Lens: Fine-tunes focus through accommodation (flattens for distance, bulges for close objects).

  • Retina: Houses photoreceptors (rods and cones).

  • Fovea: Center for sharpest visual acuity due to concentration of cones.

  • Optic Nerve: Transmits visual information to the brain.

Color Perception Theories

• Trichromatic Theory: Suggests three types of cones (red, green, blue). Color perception arises from activation levels.

• Opponent Process Theory: Suggests colors are perceived via opposing systems (red-green, blue-yellow, black-white). This accounts for color afterimages and perception of white.

Perception Processes

Selection, Organization, Interpretation

• Perception is influenced by selective attention, feature detectors, and habituation.

• Selective attention: Focusing on relevant stimuli amidst distractions (e.g., cocktail party effect).

• Feature detectors: Neurons responsive to specific types of visual inputs.

• Habituation: Reduction in response to repeated stimuli, contrasting with sensory adaptation.

Gestalt Principles

• Organize sensory experiences through principles:

  • Figure-Ground: Distinguish figure from background.

  • Proximity: Group nearby objects together.

  • Similarity: Group similar items together.

  • Continuity: We perceive lines as following the smoothest path.

  • Closure: Fill gaps to perceive complete forms.

  • Subjective Contours: Perceptions arise from the alignment and implied lines.

Depth Perception and Cues

• Monocular Cues:

  • Accommodation: Eye lens changes shape based on distance.

  • Relative Size and Height: Perceptions depend on object size vs. distance from viewer.

  • Linear Perspective and Texture Gradient: Convergence of lines suggests depth and texture clarity decreases with distance.

  • Interposition and Light/Shadow: Objects interrupting others are perceived as closer, with light direction indicating depth.

  • Aerial Perspective: Hazy views indicate distance due to air particles affecting visibility.

• Binocular Cues:

  • Retinal Disparity: Each eye sees slightly different images, aiding depth perception.

  • Convergence: Eyes turn inwards for nearby objects, cueing brain on distance.

Conclusion

• Depth perception is essential for spatial understanding, encompassing a range of monocular and binocular cues, enhancing our interpretation of the visual world.

• Understanding and mastering the concepts of sensation and perception are integral for effective learning in psychology and beyond.